SUMMARY OF OUR INTEREST IN PLANTS 401 



plants which furnish us our luxuries in the wav of fruits. 

 In eating animal products, man is still dependent apon tin- 

 grass family to furnish food for the cattle from which be 

 obtains meat, milk, cheese, and butter. For clothes, man 

 depends indirectly upon plants for the Leather and woo] 

 of the domestic animals, and directly for cotton and linen. 



Figure 440. — Tropical Vegetation. 

 Note how different the plants are from ours. 



Plants are the source of many of the materials out of 

 which houses are made and furnished. 



Some plants (bacteria) cause disease, while still others 

 provide remedies with which to cure diseases. Plants 

 please our eyes as we travel about. They keep up tin' 

 supply of oxygen in the air ; they rid the air of tin 1 carbon 

 dioxide which we have cast off; they provide employment 

 for millions of men who raise food plants, manufacture 

 them into food, and distribute them throughout the world ; 



